A Novel Synthesis Route of Mesoporous gamma Alumina from Polyoxohydroxide Aluminum
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2018
Autores
Correa, Michelle Fidelis 
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Mesoporous gamma-aluminas (gamma-Al2O3) were synthesized starting from an unusual precursor of polyoxohydroxide aluminum (POHA). This precursor was obtained from aluminum oxidation in alkaline water-ethanol solvent in the presence of d-glucose that induces the formation of a gel, which leads to the POAH powder after ethanolic treatment Precipitated POHAs were calcined at different temperatures (300, 400, 700 and 900 degrees C) resultmg m the metastable gamma-Al(2)0(3) phase. Whereas at 300 degrees C no gamma-Al(2)0(3) phase was formed, unexpectedly, mesoporous gamma-Al(2)0(3) was obtained at 400 degrees C having a high specific surface area (282 m(2)/g) and a narrow pore size distribution At higher temperatures, the aluminas had the expected decrease in surface area 166 m(2)/g (700 degrees C) and 129 m(2)/g (900 degrees C), respectively The structural change from POHA to alumina calcined at 400 degrees C occurs directly without the need to isolate the hydroxide or oxyhydroxide aluminum precursors Both POHA and transition aluminas were characterized by Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), N-2 sorption and Scanning Electron Microscopy (SEM) These findings show an alternative route to produce high standard aluminas.
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Materials Research-Ibero-American Journal Of Materials. Sao Carlos, v. 21, n. 1, p. -, 2018.